Selector switch



Jan. 6, 1931. J. I. BELLAMY 1,787,771

ssmscrox swuca Original Filed July 2, 1928 ----In 1 uen an I Jul-Ln LBElLaE HIT:

tical magnet V and that the two are in series with relay B while the line relay is operated, with the result that self-induced current from relay C flows when the shunt is removed from around relay B and joins with the main current from the magnet V. This self-induced current does not attenuate sufficiently to permit the relay to fall back during the vertical movement of the selector,

lay alone.

B the above-mentioned operation of vertic magnet V, the wipers of the switch are raised ste -by-step until they come to rest (apposite t e desired level of bank contacts.

en relay 0 operates it prepares a circuit for stepping relay D which is closed by the oil-normal contacts associated with relay D as soon as the switch leaves its normal position. Upon operating, relay D locks itself to the grounded release-trunk conductor 23.

Trunk selection When relay C falls back shortly after-the termination of series of impulses, it opens the initial circuit of relay D, leavin this relay locked to the release-trunk con actor 23, at the same time connecting up the test wiper (the middle one of the three wipers) to the junction of the stepping relay D and switchmg rela E, and extending ground at its normall c osed contacts through contacts of refly and D to the rotary magnet R0.

agnet RO'operates and advances the wipers one ste into engagement with the first set of ban contacts 1n the selected level. Near the end of its stroke, the magnet R0 opens the circuit of relay D, whereupon relay D falls back and opens the circuit of the rotary magnet, in addition to opening a further point in its own locking circuit.

If the first trunk line is idle, the rotary operation proceeds no further, and relay E is energized in the manner to be pointed out hereinafter, but, if the first trunk line is busy,

' the test wiper encounters aground potential closing a circuit through the inner upper armature, normal, of relay E armature of relay C, the interrupter contacts and associated elf-normal contacts for relay D. Relay D reoperates and again locks-to the releasetrunk conductor, at the same time closing a reoperating circuit for the rotary magnet.

The rotary magnet again operates and advances the wipers another step and again deenergizes the stepping relay.

Trunk aeizwre This operation continues until an idle trunk line is reached, which trunk line it may be assumed is the one shown in the drawing,

whereupon relay D fails to operate and relay E, which has previously been'short circuited now operates from the ground potential on release-trunk conductor 23 and in series with relay C through the interrupter and off-normal contacts. Relay D does not operate in this circuit owing to the relatively high resistance of relay E. Upon operating, relay E removes ground potential from the lower armature of relay B so as to prevent a premature release of the selector, opening the looking circuit of release relay B, leaving this re ay energized over the initial circuit through contacts of relay A. At its inner upper armature, relay E opens the test circu1t and prepares the holding circuit, connecting the test wiper to the grounded release-trunk conductor 23. At its upper and lower armatures, relay E disconnects conductors 13 and 33 from the windings of line relay A and extends them to the corresponding conductors of the seized trunk through the upper and lower wipers of the switch. Relay A now falls back and short circuits relay B, at the same time opening the initial circuit. Relay B falls back after a slight interval and prepares the release magnet circuit at its lower armature, at the same time removing the local ground potential, at its upper armature from the release-trunk conductor 23, an extension of which conductor is previouslygrounded in-the usual manner by tllie apparatus associated with the seized trun Release When the ground potential is removed from the release-trunk conductor of the established connection, when the connectionis tobe broken down, relay E falls back and, among other thin s, closes a circuit for the release magnet R a at its inner lower armature throu h the lower armature, normal, of relay D, t e lower winding of relay C and the off-normal contacts associated with the release ma I et RL. The release magnet operates an relay C reoperates at the same time. Rela C a ain closes a circuit for relay D, whic att is time extends the ground ntial applied to its winding by relay C release-trunk conductor 23, thereby guarding the selector against seizure during release. When the switch is restored to normal by the action of the release magnet RL, the ofi-normal contacts open whereu on relay C falls back due to the ogenin o the contacts associated therewit an the release may be connected together by a jumper, in

' pleted-inde endent of the lower winding ofwhich case the release magnet circuit is comrelay C, an relay 0 does not reoperate upon the release of the selector.

What is claimed is:

1. In an automatic switch, a line relay, a release relay, a control relay, contacts on said line relay for closing a circuit when the line relay is o erated, said circuit including the release re ay and operating magnet in series, self locking contacts on said release relay for closing a locking circuit for maintaining said release relay energized in series with said operating magnet, other contacts on said line relay for shunting said release relay to operate said operating magnet when the line relay falls back, and circuit connections multiplying said control relay with. said operating magnet, whereby said control relay operates the first time the magnet is operated and remains operated during suc cessive operations of the operating magnet under the control of-the line relay.

2. In an automatic switch, a line relay, a release rela a control relay, contacts on said line relay or closing a circuit when the line relay is operated, said circuit including the release relay and operating magnet in series, self locking contacts on said release relay, other contacts on said line relay for shunting said release rela to operate said operating magnet .when t e line relay falls back, circuit connections multiplying said control relay with said operating magnet, whereby said control relay operates the first time the magnet is operated and remains operated during successive operationsof the operatin magnet, a release magnet for restoring sai switch to normal, and another winding on said control relay connected in series with said release magnet so as to cause the reoper ation of said control relay during the release of the switch.

3. 'In a switch control circuit for use in an automatic telephone system, a release relay, an operating magnet, a control relay connected directly in multiple with the operating magnet, and circuit connections for supplying operating current to said release rclay through said operating magnet and control relay.

4. In a switch control circuit for use in an automatic telephone system, a release relay, an operating magnet, a control relay connected directly in multiple with the operating magnet, and circuit connections for suping magnet, circuit connections for 'supplying operating current to said release relay through said operating magnet and changeover relay, means for transmitting a series of impulses through said operating magnet and change-over relay by intermittently shunting said release relay, the windings of the 0 rating magnet and the change-over relay eing so proportioned with respect'to one another that the operating magnet falls back at the termination of each impulse when the shunt is removed from around the release relay, while the change-over relay remains operated throughout the series of impulses and falls back at the end of a short interval following the termination of the series.

6. In a switch control circuit for use in an automatic telephone system, a release relay,

magnet, impulsing circuits for operatingsaid magnets successively, the winding of said control relay being so proportioned that when the relay operates in parallel with the vertical magnet it remains operated during the entire series of impulses'because of selfinduced current in its winding, and means including said control relay for closing the impulse circuit for the secondary magnet after the primary magnet has operated.

.8. In a switch control circuit for use in automatic switching apparatus, a release re.-

.lay. two switch-operating magnets arranged to be operated successively, a control relay connected in shunt of the first operating magnet, circuit connections for applying operating current to said release relay .through the first operating magnet and said control relay, and means includin said control relay for operatin the secon operating magnet only after the rst operating magnet has been operated.

9. In a switch control circuit for use in automatic switching a paratus, two stepping magnetsaarrange to respond to two successive impulse series, respectively, a control relay having its winding connected in shunt of the first magnet, a circuit for the first magnet and the relay including a current source but having a resistance element therein which limits the current -flow to a value, below that required to operate and hold the magnet and relay, the first impulse series being delivered to the first magnet and the relay over a path excluding said resistance element, the relation between the magnet, the relay, and the resistance element being such that the magnet operates on each received impulse and falls back at the end thereof, while the relay operates on the first impulse but does not fall back until the end of the last impulse of the series, and means including contacts on said relay for preventing the net; means delivery of impulses to the second ma et until the relay has operated and has fa len back.

10. In an automatic switching system, an automatic switch having an operating magnet, a release relay, and a control relay; a conductor normally connected to the winding of the release relay, to the Winding of the control relay and to the Winding of the magfor operating said release relay by current flow through the winding of the release relay and over said conductor, and means for applying a potential to said conductor to shunt said release relay and to operate said control relay and said magnet.

11. In an automatic switch, a release relay and an operating magnet connected in series, means for temporarily connecting a source of potential to the other side of the release relay to operate the release relay in series with the operating magnet, means for applymg said current source to the junction of said release relay and magnet to operate the magnet and shunt the release relay, and a control relay connected in shunt of the operating magnet.

12. In a switching system wherein desired connections are set up by a plurality of automatic switches operated in serial relation responsive to a plurality of impulse series, an operating magnet in one of said switches arran ed to respond to the first series of impulses delivered following the taking of the switch for use, a resistance element in said switch arranged to be connected in series with said operating magnet when the switch is taken into use, means for shunting said resistance element to operate said operating magnet each time an impulse is received, and a changeover relay connected in shunt of said operating magnet and in series with said resistance'element arranged to effect a changeover operation as soon as said operating magnet has-finished operating. 05

13. In a' switching system whereiri de of automatic switches operate 'cludin ing magnet is intermittently operate is operated and main-- sired connections are set up b a plurality in serial relation responsive to a plurality of impulse series, an operating magnet in one of said switches arran ed to respond to the first series of impu ses delivered following the taking of the switch for use, a resistance element in said switch arranged to be connected in series with said operating magnet whenthe-switch is taken for use, means for shunting said resistance element to operate said operating magnet each time an impulse is received, a control relayconnected in shunt of said operating magnet and in series with said resistance element, and means including said control relay for preventing said operating magnet from responding to the next series of impulses.

14. In a selector, a release relay and an operating magnet normally connected together, a line relay, 2. front contact on said line relay for closlng a circuit through said release relay and magnet, a back contact on said line relay for shunting said release relay, and a control relay connected in shunt of said magnet.

15. In a selector, a line relay, 9. release relay energized by said line relay, an operating magnet, a control relay, parallel circuits for said magnet and control relay over which said line relay delivers ground impulses on dee'nergizin and a \circuit incontacts ong sai release relay for supplying round potential to the impulsing contacts of said line relay.

16. In a selector, 8. line relay, a release relay energized by said line relay, an operating magnet, a control relay, parallel circuits for said magnet and control relay to which said line relay delivers ground impulses on deenergizing, a circuit including contacts on said release relay for supplying ground of said ine relay, a switching relay and means for operating it after the switch has.

been operated by said operating magnet, and contacts on said switching relay for openin the ground supply connection to the sai impulsing contacts of the line relay.

17. Inv a selector, a release relay and a changeover relay connected in series, pri- ,mary and secondary operating magnets in sand selector, said primary operating mag net being connected in shunt of said control rela means for shunting said release relay to net and controlrelay', whereby said 0 eratand said control rela tained operated uring the entire time impulses are being delivered to the primary trolling function upon falling back at the end of the operation of :the primary magnet,

eliver impulses to said operating mag-- otential to the impulsing contacts operating magnet, and circuit connections whereby S8.1d control relay exercises its conin shunt ofsaid primary operating magnet and arranged to cause the selector to change over-from its primary movement to its secondary movement at the end of the primary movement.

19. In an automatic switch, a release relay and an operating magnet connected in series, means for shunting said release relay to send current impulses to said operating magnet, a control relay so connected to the magnet and release-relay circuit that it receives current continuously through said release relay and said shunt circuit while impulses are being sent to said magnet, said relay being so adjusted that it operates when the first impulse is delivered to the magnet and remains operated until the last impulse has been delivered, and means. whereby said controlrelay upon falling back upon the termination of the transmission of impulses to the magnet performs an operation necessary to the successful operation of the switch.

20. Ina selector, an operating magnet, a release magnet, and a control relay; and means for operating said control relay in parallel with said operating magnet while the selector is being operated, and-for operating said control relay in series with said release magnet while the selector is being released.

21. In a selector,primary and secondary operating magnets, a release magnet, a changeover relay arranged to control the secondary operating magnet so that it is not operated until after the primary magnet has been operated, circuit connections for operating said changeover relay in shunt of said primary magnet during the primary operation' of the selector, and circuit connections for operating said changeover relay in clrcult with said release magnet while the selector is being released.

22. In a selector having an operating magnet and a release magnet, a changeover relay operated in parallel with the operating mag- .net while the switch is being operated, and

means for reoperating the changeover relay while the selector is being released.

23. In a selector having an operating magnet and a control relay connected in parallel circuits whereby the control relay is operated when the operating magnet is operated, and means for subsequently reoperating said control relay without reoperating said magnet.

24. The method of causing the changeover relay of a selector to remain operated between the transmission of successive impulses thereto which consists in maintaining it continuously shunted during an impulse series and in maintaining a priming current throu h the relay between impulses of a value insu c tepit to maintain the relay continuously opera e 25. The method of causing the changeover relay of a selector to remain operated, after it responds to the first impulse of a series, until all impulses of the series have been received, and for permitting it to fall back then, which consists in maintaining the relay continuously shunted during an impulse series, in providing an alternative circuit for the relay between impulses, and in restricting the current flow in the alternative circuit so that the relay will hold up therethrough only momentarily.

In witness whereof, I hereunto subscribe my name. I JOHN I. BELLAMY.

CERTIFICATE OF CORRECTICN.

Patent No. 1,787,771.. Granted January 6, 1931, to

JOHN 1. BELLAMY.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 3, lines 27 and 42,

cla ms I and 2, respectively, for the word "multiplying" read multipling; and

that the said Letters Patent should be read with these corrections therein that the same may conform-to the record of the case in the Patent Office.

Signed and sealed this 24th day of February, A. D. 1931.

v M. J. Moore, (Seal) Acting Commissioner of Patents. 

